1. Field of the Invention
The present invention relates to a light emitting device for ornamenting a mark with light. The invention is to be applied to an automotive emblem, for example.
2. Description of the Related Art
Conventionally, various contrivances have been made to improve the design and luxuriousness of the exterior appearance of vehicles, etc. Among these, it is a practice to provide light emission on light illuminate light to a mark (emblem) attached on the body at the rear of a vehicle. For example, JP-UM-A-5-1597 and JP-A-9-202178 disclose a structure that a plurality of LEDs are arranged in back of a mark body of light-transmissive material so that LED-based light can be extracted through the mark body thereby causing light emission on the mark.
In the related structure, mark viewability is improved by displaying the mark with light emission in the night. However, because LED-based light as a point light source is directly used in light emission on the mark, the light-emission mode as to the mark includes an extreme high intensity region correspondingly to LED positions. In other words, the light emission mode is based on granularity thus being inferior in design and short of luxuriousness.
Therefore, it is an object of the present invention to provide a structure for providing a mark well in design and high in luxuriousness.
The present invention, for achieving the foregoing object, comprises the following structure. That is, the light emitting device comprises a mark body, a substrate, a first surface of which the mark body is arranged, an LED mounted on a second surface of the substrate, and a light guide arranged on the second surface of the substrate, including a first surface for introducing a light emitted from the LED, a second surface for emitting a light and a third surface opposing the first surface on which a light is reflected in a diffused manner. Incidentally, the third surface of the light guide includes a light diffuse reflection surface.
In the above structure, firstly, LED-based light in the second surface is emitted toward the light guide. The light is introduced into the light guide through the first surface of the light guide and finally emitted at the second surface of the light guide. Here, the third surface of the light guide includes the light diffuse reflection surface, which enhances light diffusion at the inside of the light guide and prevents light from leaking at the third surface. As a result, light is emitted with brightness and reduced in irregular brightness through the second surface of light guide, to indirectly illuminate the mark body from the back thereof. In such an illumination state, it is natural to obtain an effect that visibility of a mark is improved with light while high staging effect is offered. Thus, the mark is superior in design and full in luxuriousness. Meanwhile, because a stereoscopic expression can be felt as if the mark stands out due to the occurrence of light in back of the mark body, unpredictability can be staged in addition to design and luxuriousness superiority.
Meanwhile, the invention is a light emitting device comprising:
a mark body;
a substrate arranged in back of the mark body;
an LED mounted on an opposite surface of the substrate to the mark body;
a light guide arranged on a closer side of the substrate to the LED and having an upper surface serving as a light introducing surface for introducing LED-based light, a side surface serving as a light emitting surface and a backside having a plurality of protrusions in a rib form.
In the above structure, LED-based light is introduced through the upper surface of the light guide and finally extracted from the side surface of the light guide. The major part of the light introduced in the light guide undergoes a reflection effect due to the light guide backside in the course before extraction to the outside. Here, according to the above structure, when the light emitting device is attached to a mount part such as a vehicle body, rib-like protrusions can be utilized that are provided in a backside of the light guide. Namely, the light emitting device can be attached by connecting between the tips of the rib-like projections and the mount part by means of a double-sided tape or an adhesive. In this case, the rib-like projections at tips only are directly involved in the joining wherein the other region of the light guide backside is left in an open state. Accordingly, in this region, there is eliminated light loss or reflection efficiency lowering due to the influence of the joining. In this manner, because of reduced light loss at the backside of the light guide and preferred reflection efficiency as well, excellent light guide effect is presented to improve light utilization efficiency. As a result, bright light emission is available with less irregular brightness through the side surface of light guide, thus indirectly illuminating the mark body from the back thereof. In such an illumination state, it is natural to obtain an effect that mark visibility with light is improved while presenting a high staging effect. Thus, the mark is superior in design and full in luxuriousness. Meanwhile, because a stereoscopic expression can be felt as if the mark stands out due to the occurrence of light in back of the mark body, unpredictability can be staged in addition to design and luxuriousness superiority.
Meanwhile, according to the above structure, the regions involving in connection to the mount part such as a vehicle body exist distributing in a rib form, to enable joining at a high bonding force over a broad area. This makes it possible to firmly fix the light emitting device of the invention to the mount part.